Part 1. The Field of the Invention
This invention relates to novel, improved correction compositions for correcting markings recorded on pressure-sensitive chemical recording materials and to novel, improved processes for correcting markings on pressure-sensitive chemical recording materials.
Part 2. Description of the Prior Art
Pressure sensitive chemical recording materials are known products of commerce. They usually take the form of a set of two sheets of recording materials, one having a coated back (CB) and the other having a coated front (CF). The coated back sheet usually provides the cover sheet for the set and carrys on the back surface a color-providing material which is usually colorless. The coated front sheet carrys color developer material on the front sheet, and the back and front sheets are arranged in superposed relationship. In practice, pressure is applied to the surface opposite the back sheet surface such as by a writing, typing, or printing instrument to cause release of the color-providing material for interaction with the color developer material. Upon separation of the sheets, a visible image pattern is provided in the front surface which corresponds to the pattern of applied pressure.
Compositions for correcting conventional ink markings on recording materials such as paper are also known products of commerce, and their desired combination of performance characteristics are well defined. Essentially the primary combination of performance characteristics of such compositions involve the capability to completely and effectively cover erroneous markings on a paper surface and provide a film for corrected markings which is strongly bonded to the surface but also sufficiently flexibe so that the film will not be removed from the surface such as by cracking or flaking when the corrected sheet is subjected to handling and folding conditions. Additionally, the film should have a color closely matching the color of the paper and provide a texture or surface closely corresponding to those of the paper. Other desired performance characteristics include good storage stability, flow and viscosity characteristics providing easy and even application and, fast drying so that corrections can be made relatively quickly. While the above-described compositions are effective for correcting conventional ink markings, they are not suitable for pressure-sensitve recording materials. In addition to all the performance characteristics described above, an effective composition for correcting markings in chemical pressure-sensitive recording materials must be both capable of covering the marking and also provide means to effectively restore the imaging capability of the recording materials to provide a visible, corrected marking in the covered area. The present invention is directed to the outstanding need in the art to provide an effective correction composition for presure-sensitive chemical recording materials and presents an especially effective response to that need.